Cotter pin with interlocking spreader



y 1960 5. J. STRID 2,937,558

CUTTER PIN WITH INTERLOCKING SPREADER Filed April 1, 1957 24 2? VII 56 22 25% H 73 INVENTOR SVEN J. STRID BY %M M ATTORNEY United States Patent 2,937,558 CO'ITER PIN WITH INTERLOCKING SPREADER Sven J. Strid, Chicago, Ill., assignor to T & S Corpora tion, Chicago, Ill., a corporation of Illinois Filed Apr. 1, 1957, Ser. No. 649,906 1 Claim. (Cl. 85-8.1)

My invention relates to cotter pins, with special reference to cotter pin assemblies constructed for self-spreading action, and is directed specifically to improvements in the spreader member employed in such assemblies.

In a cotter pin of the present type, the assembly comprises a cotter pin member having the usual pair of arms in combination with a spreader member extending between the two arms. During shipment and handling of the assembly prior to application, the cotter pin member and the spreader or wedge member are in retracted positions relative to each other. When the cotter pin is ultimately driven into place for service as a retaining means, the spreader member is held stationary at a certain point and the subsequent relative longitudinal movement of the cotter pin member causes the arms of the cotter pin member to be wedged apart at their free ends by the spreader member. The general construction of such a spreader member in a cotter pin assembly, as taught by the prior art. is shown in Strid Patent No. 2,431,664.

This is a continuation-in-part of application Serial No. 574,177, filed March 27, 1956 and now abandoned.

Generally, such a spreader member is fabricated in steps, including cutting a sheet metal blank of suitable configuration and bending the blank to form a pair of spaced side flanges of tapering configuration to serve as wedge means in the spreading of the cotter pin arms.

While this general form of spreader construction has been employed for many years, there has been a tendency for the spaced side flanges to deflect laterally under the severe shock loads to which it is subjected during the application of the assembly. In these instances, this lateral yielding movement of the side flanges has resulted in an incomplete spreading action on the pin member.

One of the principal objects of the present invention is to improve the construction and the method of con struction of such a spreader member by providing an integral connecting strip between the outer end of the flanges that materially enhances their resistance to bending and distortion under the severe loadings imposed.

In general, this object is attained by altering the initial configuration of the spreader blank to a configuration that includes, in addition to the laterally projecting portions, an endwise projecting portion or flange which extends between and joins with the free or outer end of the lateral projections or flanges. The blank is formed in a single operation and the resultant three sided wedge structure has proven to be rigid and unyielding and apparently suflers no adverse etfects during the forming operation.

Another object of the invention is to improve the locking action between the pin and its spreader by providing both with interengaging notches or serrations that restrain movement of one of the elements with respect to the other.

Other objects and advantages of my invention will be obvious or become apparent on a study of the following description and the accompanying drawings in which like numerals are employed to designate like parts throughout the same.

Figure 1 is a side elevation of a typical cotter pin assembly including my improved spreader member;

Figure 2 is a plan view on an enlarged scale of a spreader member constructed in accordance with my invention;

Figure 3 is an end view of the inner or left hand end of the spreader member as it appears in Figure 2;

2,937,558 Patented May 24, 1960 Figure 4 is a side view of the spreader member;

Figure 5 is an end view of the outer or right hand end of the spreader member;

Figure 6 is a fragmentary plan view on an enlarged scale of the outer or Wedge end of the spreader blank according to my invention;

Figure 7 is a plan view similar to Figure 6 but illustrating the spreader member after it has been formed with a wedge end;

Figure 8 is a side view of the wedge end of the spreader of Figure 7;

Figure 9 is a longitudinal section taken as indicated by the line 9-9 of Figure 7;

Figure 10 is a side elevational view of a modified cotter pin assembly in which the principles of my invention are employed, shown applied to a bolt that is indicated in broken lines;

Figure 11 is a plan view of the cotter pin member forming a part of the assembly shown in Figure 10;

Figure 12 is a side view of the cotter pin member shown in Figure 11;

Figure 13 is an end view of the left hand end of a cotter pin member shown in Figure 12;

Figure 14 is a plan view of the spreader member forming a part of the cotter pin assembly shown in Figure 10;

Figure 15 is an end view of the inner or inwardly disposed (right hand) end of the spreader member of Figure 14;

Figure 16 is an end view of the outer or outwardly disposed (left hand) end of the spreader member shown in Figure 14; and

Figure 17 is a side elevational view of the spreader member shown in Figure 14.

In the cotter pin assembly shown in Figure l, the cotter pin member, generally designated as 20, is formed from a single piece of suitable half round stock, and comprises the usual pair of arms 21 interconnected by a loop 22, the arms being sprung together. Inserted between the arms 21 is a spreader member 23 having laterally spaced side flanges or projections 24 connected by an end flange or projection 25 which is bridged across the outer end of the spreader member and thus this outer end is of the usual tapered configuration and serves as a wedging arrangement for spreading the arms 21 of the cotter pin.

At the inner end of the spreader member 23 is a pair of laterally extending wings 26 which serve a dual function. On the one hand, they provide an enlarged abutment that limits the movement of the spreader member into a bore when the cotter pin assembly is being installed, whereby the spreader member is held stationary during the final movement of the cotter pin member into the bore. Thus, relative movement between the spreader member and the cotter pin member produces the desired spreading action at the ends of the arms 21. In addition, the wings 26 limit lateral movement of the spreader member relative to the cotter pin member prior to installation of the device, and for this purpose the two wings are sufliciently bent to engage the opposite sides of the cotter pin member 20.

The particular spreader member shown in Figure l is also provided with small tabs or flanges 27 on its opposite sides that fit snugly against the cotter pin member 20 to prevent lateral movemnet between the spreader member and the cotter pin member at a second point. The function of these wings 26 and tabs 27 may be embodied in other forms from means well known to those skilled in the art without departing from the present invention.

In the specific embodiments disclosed herein, it will be seen thatt he sheet metal blank, shown in Figure 6 from which the spreader member is formed comprises a body. portion 28 with parallel side edges 30 and having an enlargement at one end comprising diverging side edges 31 and a generally rounded-end edge 32 that overlaps the side edges. Opposite sides of the blank are formed with recesses 36 which are located at the base of the diverging side edges 31 and which permit the outer end of the spreader blank to be bent along the dashed lines, indicated at 37, in a clean cut manner that avoids pinching of material adjacent the base of the side edges and that does not impose any strain on the metal between the two marginal recesses 36. These recesses may be of varying form and are fully described in my aforesaid prior patent.

My present invention differs from prior art spreader arrangements in that it includes the end projection 32 that overlaps and connects the side projections 31. The end projection is of a generally rounded shape though its outer end may be flat as indicated at 39. The disclosed arrangement permits the blank to be formed into a completed Wedging structure in a single forming operation. Since the resulting three sided wedge structure includes a flange that is bent around right angled corners there is necessarily some pinching and distorting of the materail constituting the wedge; however, with the disclosed arrangement it has been found that the resulting structure far exceeds the prior art arrangements with respect to strength and rigidity. While the end projection material is strained in some respects by the forming operation that makes it an end flange, its reinforcing action is nevertheless sufficiently strong that the side flanges formed by bending projections 31 are positively prevented from deflecting laterally. Actually they will yield under compression before deflecting.

While the basic simplicity of the present invention is immediately apparent, it is interesting to realize that the cotter pin assemblies of the general character with which the present invention is concerned are employed by a. vast number of individuals familiar with the tendency of the side flanges to deflect laterally when unusually severe shock loads are applied during installation. In spite of the tremendous number of people familiar with this problem, no satisfactory answer has, until the present time, been forthcoming. It is worthy of note that the basic simplicity in the cotter pin assembly is not lost, nor is the manufacturing cost increased. There is still required only a single forming operation.

The embodiment of Figures 17 is basically the same as that of Figures l9, but includes interlocking notches or serrations for better restraining movements of the cotter pin assembly elements with respect to each other. In this embodiment of the invention, the flat undersurface 50 of the pin member 20a is formed at the ends of arms 21a of this member with a plurality of notches or serrations 52. The side flanges 31a of spreader member 23a along their rims that comprise one diverging edge or face thereof are formed with a plurality of like or mating serrations or notches 54 adapted to cooperate with the notches or serrations 52 on one arm of the pin member while the undersurface 56 that forms the other diverging edges or faces of the side flanges of the spreader member is formed with similar notches or serrations 57 adapted to cooperate with the notches or serrations 52 of the other arm of the pin member.

Thus, when the assembly of Figures 10-17 is past from right to left through the opening 58 of diagrammatically illustrated bolt 60, the left hand ends of the pin member arms 21a will be flat or aligned with the remaining portions of the respective arms (as shown in Figure ll). When the laterally extending wing members 26a of the spreader member engage bolt 60, movement of the spreader to the left stops. The cotter pin member then is completely forced home by a tap or two with a hammer on the loop 22a thereof. The spreader member being fixed against further movement to the left, the left hand ends of the pin member bend outwardly of each other as dictated by the slopes of the wedge like shape formed by side flanges 24a and end flange 25a.

The serrations or notches 54 and 57 engage and interlock with the respective notches or serartions 52 to positively lock the members 20a and 23a against separating movement with respect to each other.

Both the spreader members are bent somewhat about the line 61 of Figure 14 to insure that surface 56 acts as a wedging surface.

It will be apparent to those skilled in the art that various changes and substitutions departing from the described construction and procedures may be made within the scope of my appended claim.

I claim:

A cotter pin assembly including a cotter pin member formed from a length of half round stock bent double to define two adjacent rectilinear arms connected by a looped portion, with the flat surfaces of said arms opposing each other, and a spreader member interposed between said arms, said spreader member being formed from a strip of sheet metal and including a pair of laterally projecting wings at one end thereof, a pair of spaced tapering flanges at the other end thereof projecting normally of one side of said strip, and a pair of laterally projecting tabs intermediate said ends of said strip, said one end of said spreader member being positioned adjacent said looped portion of said cotter pin member and said other end of said spreader member being positioned adjacent the free ends of said arms with said flanges projecting normally of said flat surfaces of said arms, said wings and said tabs being disposed in engagement with the respective arms of said cotter pin member, said flanges having their portions of major dimension at the terminous of said other end of said strip and terminating in relatively coplanar wedge surfaces adapted to engage the fiat surface of one of said arms and tapering from said one side of said strip, the other side of said strip including a surface portion diverging from said coplanar surfaces of said flanges from their portions of minor dimension to the terminous of said other end of said spreader member, said surface portion of said other side of said strip defining a wedge surface adapted to engage the flat surface of the other of said arms, said wedge surfaces tapering at substantially equal angles from the respective sides of said strip, said surface portion of said other side of said strip and said coplanar surfaces defining a wedge shaped channel-like portion adapted to engage said flat surfaces of said arms to deflect the free ends of said arms laterally of said assembly, and an end wall rigidly and integrally uniting said flanges and said terminous of said other end of said spreader member, said end wall terminating in an edge surface that is substantially aligned with the plane of said coplanar wedge surfaces of said flanges, whereby, said flanges are rigidly restrained at both ends thereof from lateral deflection in either direction and said end wall edge surface forms a part of the Wedging configuration defined by said coplanar wedge surfaces of said flanges, said wedge surfaces and the flat surfaces of said arms that they engage being formed with complementary interengaging notches formed to oppose withdrawal movement of said spreader member longitudinally of said arms.

References Cited in the file of this patent UNITED STATES PATENTS 491,019 Manson Jan. 31, 1893 1,234,487 Raeger July 24, 1917 1,374,713 Bell Apr. 12, 1921 .487558 Gotham Mar. 18, 1924 l,582,751 Housteau Apr. 27, 1926 1,768,670 Dedering July 1, 1930 2,l2l,425 Cooke June 21, 1938 FOREIGN PATENTS 602,172 France Dec. 18, 1925 

